Process for scaling tubes



June 11, 1935. R. TRAUT PRocEss FOR HSCALING' TUBES [/2 uenfor:

Filed Nov. 22, 1933 Patented June 11, 1935 UNITED STATES PATENT OFFICE Application November 22, 1933, Serial No. 699,147 In Germany January 14, 1933 3 Claims.

It is known to scale butt-welded tubes. by passing them, after they have cooled, through a dimensioning rolling mill at a certain temperature, with a view to dislodging the scale by the pressure of the rollers and the friction on the annular discharge guide members. Such removal of the scale has, however, been found to be incomplete, because of the wear on the discharge rings, which in due course sets in more or less rapidly. To change the rings involves stopping work, and to avoid this a less thorough scaling has to be accepted.

To avoid this disadvantage the discharge rings are. according to the invention, provided-in the form of annular spray nozzles, and water under high pressure is discharged from the nozzles and directed on to the surface of the tube, the shrink ing action of the cold water on the hot iron and the mechanical efiect produced by the powerful jet of water combining to cause the complete removal of the scale from the tube.

Apparatus for carrying out the process of the vention is illustrated by way of example in the accompanying drawing.

Referring to the drawing, a are the dimensioning rollers and b is the frame of the dimensioning rolling mill. is the tube to be scaled, d are the rollers of the the dimensioning rolling mill, and e are the rollers of the discharge train beyond the dimensioning rolling mill. In front of the dimensioning rollers 11 is positioned the tube feeding device I and bebind the rollers a is disposed the scaling device 9; the scaling device g carries the guide funnel h on the side facing one of the dimensioning rollers while it is provided at the opposite end with the spray device which consists of the casing i and the nozzle member k screwed into it. The nozzle member In is so screwed into the casing i that a narrow annular slot remains between the inner circumferentialedge of the nozzle member k and an innerannular projecting flange of the casing i; the width of the slot can be regulated by screwing the nozzle member k backwards or forwards. To the bottom of the scaling device 9 is fitted a discharge pipe m. In the casing i a water-supply pipe n is connected at one or more positions and is directed towards the annular slot, the water-supply pipe 12 being at the same time connected to a valve 0 actuated by the electromagnet q the current to which is controlled by the switch 1' provided in front of the rolling mill and actuated by a lever s resting upon the feeding device I. The retarding relay t introduced into the circuit prevents instantaneous stoppage of the electromagroller feeding train in front of net q and therefore the valve 0, so that when the switch 1' that controls the current is opened the water spray device is not at once disconnected but remains in operation for a further short period so that the rear end of the tube is scaled after the 5 tube leaves the tube feeding device f. I

The apparatus operates as follows:

The tube 0, which has been cooled to a predetermined temperature, for example, 850 C., and which the rollers 11 of the train of guide rollers convey to the dimensioning rollers a shortly before it passes into the dimensioning rollers, strikes against the lever s of the switch 1', which rests upon the tube feeding device f; this causes current to flow through the electro- 15 magnet q, which is controlled by the switch 1'. and so the valve 0 is opened by the electromagnet. The water under pressure is thus caused to pass through the tube 12 to enter the annular chamber l in the nozzle casing z and it leaves the latter in the formof an annular jet passing through the annular slot formed between the casing i and the nozzle member is, being then dashed at an inclination against the surface of the tube, some of the water passing into the tube through the front end. In this way the scale adhering to the tube is completely removed. The scale mixes in the scaling device g with the outfiowing water and is discharged through the discharge pipe m into the sinter channel provided below the rolling mill where a sinter collecting box is advantageously provided.

Immediately the rear end of the tube 0 has left the tube feeding device f and passed between the dimensioning rollers a. and lever s which operates the switch r falls under gravity back into its initial position, which action breaks the electric current circuit; this in turn causes the valve 0 to be closed by an electromagnet q so that the supply of water under pressure to the 0 spray nozzle is cut off. The closing of the electromagnet and the cutting off of the supply of water under pressure is delayed by the retarding relay t provided in the circuit until the rear end of the tub has passed through the spray device.

The cycle of operations described recommences when the next tube is passed in. If the tubes are brought up for treatment quickly one after the other the control of water under pressure may be dispensed with, the water supplying tube n being placed in permanent connection with the pipe 10 which supplies the water under pressure, an ordinary valve being employed. In this case water under pressure is continuously introduced into the scaling device and the stoppage can be efiected by hand by means of the valve, only when the device is inoperative.

The water pressure is produced by means of a small pump driven by the motor operating the dimensioning rolling mill and it may be supplied to the spray nozzle by the tube n or by the interposition of the automatically controlled valve 0. The valve 0 may be actuated by some other motive force such as compressed air or water under pressure, the switch 7' being constructed as a compressed air valve or a valve controlled by water under pressure.

Finally the valve 0 may replace the switch 1 and the valve be actuated directly by the lever s.

I claim:

1. A process for removing 'scale from tubes and round bars of metal, consisting in cooling the work in air after the welding or rolling operation below a temperature of about 850 C., passing it through a measuring rolling mill and. spraying it with liquid under pressure at an angle and in a direction opposed to its direction of movement for the removal of the scale by cooling action and by mechanical action.

2. Apparatus for removing scale from tubes and round bars of metal, consisting of a measuring rolling mill and a scale-removing box, said scale-removing box comprising a guide funnel for the work disposed adjacent the rolling mill, and an annular spraying nozzle in a position removed from the rolling mill, said annular spraying nozzle being concentric with the path of the work and delivering liquid towards the axis of thelguide funnel.

3. Apparatus according to claim 2, having the nozzle consisting of a casing and an adjustable nozzle member forming between them an outlet directed at such an angle to the path of the Work that the sprayed liquid enters the work when the work is a tube.

' RUDOLF TRAUT. 

